The present disclosure relates to an image display apparatus. Further, the present disclosure relates to a variable lens array.
There are various image display apparatuses capable of stereoscopic viewing in a way that an image viewer views two images having parallax. The methods of the image display apparatuses capable of stereoscopic viewing are roughly classified into two methods: a method using glasses in which a parallax image is separately presented to the right and left eyes by glasses; and a naked-eye viewing method in which a parallax image is presented to the right and left eyes without using glasses. As an image display apparatus using the naked-eye viewing method, an image display apparatus, in which a lens array such as a lenticular lens is combined with an image display section for displaying a two-dimensional image, has been practically used.
FIGS. 30A and 30B show conceptual diagrams of operations of the image display apparatus in which the lens array having lens lines is disposed between the image display section and an image viewer.
As shown in FIG. 30A, a bundle of rays, which is emitted from pixel groups indicated by the signs R1, R3, R5, R7, and R9, reaches the point of view 2. Further, as shown in FIG. 30B, a bundle of rays, which is emitted from pixel groups indicated by the signs L2, L4, L6, L8, and L10, reaches the point of view 1. As described above, at a position at a predetermined distance from the image display section, the image at the point of view 1 and the image at the point of view 2 are separately viewed.
The left and right eyes of an image viewer are positioned at the point of view 1 and the point of view 2, the image for the left eye is displayed by the pixel groups indicated by the signs L2, L4, L6, L8, and L10, and the image for the right eye is displayed by the pixel groups indicated by the signs R1, R3, R5, R7, and R9. In this case, the image viewer recognizes the images as a stereoscopic image.
Meanwhile, in the image display apparatus capable of stereoscopic viewing, it is preferable to display a normal image (two-dimensional image) without any problem. In other words, it is preferable to adopt a configuration capable of switching display of the stereoscopic image and display of the normal image. When the refractive power of the lens line of the lens array is variable, it is possible to switch display of the stereoscopic image and display of the normal image.
For example, as shown in FIG. 2 in Japanese Unexamined Patent Application Publication No. 2001-133918, as a variable lens array capable of varying the refractive power of the lens line, a variable lens array has been proposed that has a structure in which a liquid crystal layer is disposed between a pair of transparent substrates having transparent electrodes. In the variable lens array with the structure, the lens line is formed of gradient index lenses using a liquid crystal material, and is thus able to vary the refractive power of the lens line by changing the voltage between the pair of substrates.